Machine for receiving electric waves.



R. GOLDSGHMIDT MACHINE FOR RECEIVING ELECTRIC WAVES.

I APPLICATION FILED DEO.10, 1912. 1,087,1 1 3.. I Patented Feb. 17,1914.

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APPLICATION FILED DEG. 10, 1912. 1,087,1 1 3, Patented Feb. 17, 1914.

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23 rvceziver UNITED STATES PATENT o FFIcE.

BUDOLF GOLDSCHMIDT,

OF BERLIN, GEBMANY.,

HACHINE FOR RECEIVING- ELECTRIC WAVES.

To all 'whom it may concern Be it known that I, Runonr GoLnscHMm'r,

, a citizen of Germany, residing at Berlin,

Germany, have invented a new and Improved Machine for Receiving ElectricWaves, of Which the following is a specification. v M

This invention relates tofa novel machine for changing the interceptedenergy of electric waves, so as to render them perceptive in telephonesor other receiving apparatus.

In a copending patent application filed by me March 29th, 1911 underSerial No. 617,735 for an apparatus for and method of receiving electricwaves, I have described the use of an asynchronous transformer forreducing the frequency of the intercepted current. In the present patentapplication, I employ entirely different means for accomplishing thisresult of making the waves perceptible, these means consisting of acommutator, which is rotated asynchronously relatively to the frequencyof the intercepted electric waves as more fully pointed out in theappended specification and claims.

ception of high frequency currents; Fig. 3

a. curve of the received alternating current;

F ig. 3 a curve of the resulting direct current; Fig. 3 a curveillustrating a modified form of the resulting current; Fig. 4 a curveillustrating a further modified form of the resulting current; F 1g. 5 aside new of a: pair of rotary converters connected in casverter of Fig.5; Fig. 7 a curve of the current delivered by the second converter ofFig. 5, and Figs. 8 and 8 are diagrams,

similar to Figs. 7 and 7", showing the cur rent form, in case one of thecommutator segments is omitted.

In order to elucidate the underlying prin- Specification of LettersPatent.

ciple of my invention, 'a rotary converter has been diagrammaticallyillustrated in Fig. 1, in which the letter A designates a rotary ironcore provided with a short-circuited winding A At the points a, I),0,01, winding A is respectively connected to the segments 1, 2, 3, 4 ofa commutator B,s aid segments being engaged by the brushes G,

Winding A at the points e, f, g to the slip-rings h, i, 9' respectively.If the latter are supplied with three-phase current and if commutator Bis rotated with'such a speed that it performs one complete revolutionduring each period of the alternating current, direct current isfurnished by brushes C, D.

For receivin high-frequency currents, the arrangement s own in Fig. 1may be considerably simplified. As single phase current is generallyused in wireless telegraphy and telephony, this current may be changedto three-phase current through phase divialthough this method is notpreferred. It

I is also of advantage to omit the wound core In the accompanyingdrawing: Figure 1. is adiagrammatic view of a conventional rotaryconverter and its connections; Fig. 2 a similar view of a simplifiedconstruction thereof adapting the converter for the re-;

A and to reduce the numberof commutator segments as much as possible.Thus in Fig. 2, the commutator is shown to comprise but two segments 1and 2 which are connected to slip rings is and Z. The latter are in turnrespectively connected to the antenna and ground, while the currentistaken off segmen-ts 1 and 2 by brushes C and I). It is of courseimmaterial whether the commutator rotates or whether the brushes rotate,2 showing the commutator made rotatable. It may however here be statedthat the method is in no wise changed if the tension is divided by meansof inductances or condensers, and if additional commutator segments areconnected to the dividing points. If the commutator is rotated insynchronism with the arriving alternating current, and the brushes C andD are correctly adjusted, said alternating current (F 3) is transformedinto direct current (Fig. 3 The production of direct current in themanner described however, is very difiicult, which is the more true withcurrents of such high frequency as are used in wireless telegraphy.

Patented Feb. 1 7, 1914. Application filed December 10, 1912. Serial110. 735,937.

is furthermore connected ram Since exact'synchronism is not the solecondition for the production of direct current, but as a minute andunvariable adjustment of the brushes is also required, the generation ofdirect current appears to be practically impossible. If the commutatoris rotated slightly slower or quiclrer than true synchronism with theintercepted or arrived current would require, brushes C and D willfurnish a current, the tension of which is illustrated in Fig. 3. Byconnecting a telephone or a string-galvanometer, the membrane of theformer or the string of the latter will receive an alternating current,the periodicity of the amplitude variation of which equals:

MIL-ing wherein w represents the intercepted or arrived periodicity, n,the synchronous number of revolutions of the commutator and a, theactual number of revolutions thereof. Of course, the resulting currentis not a pure alternating current, but a peaked current as illustratedin Fig. 3. These peaks however may be readily done away with by theinsertion of inductances or other tuning means, in order to produce apure alternating current of the desired periodicity. This procedure maysometimes be unnecessary, as

the peaked alternating current is of ample efliciency to actuate themembrane or string. Pure alternating current may be obtained if desiredby tension-division and phasesplitting as above described. The efiect ofthe produced secondary current equals that of a pure alternating currentas indicated by the dot and dash line,.Fi'g. 3. If there is no need fora high efiiciency of the commutator machine, the construction of thelatter may be considerably simplified by omitting one of the twocommutator-segments, thus replacing the commutator by a starwheel whichfor the purpose of this invention is an equivalent thereof. The currentobtained in this way is reproduced by the curve shown in Fi 4, fromwhich it is obvious that 50% o the energy is not utilized by omittingthe second commutator segment. As the number of revolutions would bevery high when using but one or two commutator segments, the speed maybe readily reduced by increasing the number of segments.

In case mechanical reasons forbid thev transformation of the current inbut a single machine, a plurality of machines may be connected incascade form, as illustrated in oam 1e brushes C D Sliprings S areconnected further frequency reduction of amplitude variation by rotatingcommutator B asynchronously relatively to the frequency of the currentdelivered from brushes C, D. The effect will be more clearlydemonstrated by synchronously rotating both converters, z. c. if noattempt is made to generate lowfrequency variation, but to producedirect current as illustrated in Fig. 3 The curve shown in Fig. 7represents the current after the first transformation, while Fig. 7illustrates it after the second trans ormation. In case every secondcommutator-segment is omitted, the current assumes the form illustratedin Fig. 8*, the curve of the current after the second transformationbeing shown in Fig. 8

The cascade-arrangement above described, may be simplified by repeatedlyreturning the resulting secondary current to one and the same machine,until the desired frequency has been obtained, as illustrated in Fi 6.The intercepted current is conducte to slip-rings S to be taken 0H fromthe commutator-segments by brushes B C After passing the tuning means a,the current is returned to slip-rings S to be again transformed andreturned over tuning means a The resulting current is finally conductedto receiver T, whose circuit is tuned to the desired frequency variationby the tuning means a I claim:

1. In a machine of the character described, means for absorbing energyof high frequency from a passing electromagnetic wave, a commutator,means for conducting said absorbed energy to the commutator, means forrotating the commutator asynchronously relatively to the frequency ofthe absorbed energy, and energy-receiving means connected to thecommutator.

2. In amachine of the character described, means for absorbing energy ofhigh frequency from a passing electromagnetic wave, a commutator, meansfor conducting said absorbed energy to the commutator, brushes engagingthe same, means for rotating the commutator asynchronously relatively tothe frequency of the absorbed energy, and energy-receiving meansconnected to said brushes.

3. In a machine of the character described,

means for absorbing energy of high frequency from a passingelectromagnetic wave, a first and a second commutator, brushes engagingthe same, means for conducting said absorbed energy to the firstcommutator,

means for connecting the brushes of the first commutator with the secondcommutator, second commutator, and current-receiving means for rotatingthe first commutator means connected to the brushes of the secondasynchronously relatively to the frequency commutator.

of the absorbed energy, means for rotating RUDOLF GOLDSCHMIDT. thesecond commutator asynchronously to Witnesses: the frequency of thecurrent delivered from HENRY HASPER,

the brushes of the first commutator to the WOLDEMAR HAUPT.

